A shrinkable tube covering an object by shrinking due to an application of heat and reducing in diameter (a so-called heat-shrinkable tube) enables a reliable sheathing performance to be obtained with a simple procedure, and therefore is widely used for a variety of applications such as bundling electric wires or the like; protecting electric wire terminals or electric wire connections; and insulation.
For example, in a case where a wire harness is to be assembled by bundling a group of wires using a shrinkable tube, a worker inserts a group of wires to be bundled into an interior of the shrinkable tube, then applies heat to the shrinkable tube. This causes the shrinkable tube to contract and reduce in diameter, adhering to an outer circumference of the group of wires and tightening around them. Thus a wire harness can be obtained in which a group of wires is tightly bundled.
Although a conventional shrinkable tube has excellent sheathing performance, due to the tubular shape of the tube, the conventional shrinkable tube can only be used with head-insertion. For example, in a case where a group of wires is to be bundled by the shrinkable tube, a connection terminal connected to a tip of each wire must be temporarily removed in order to pass the group of wires through the interior of the shrinkable tube, and once the group of wires has been passed through the interior of the shrinkable tube, the connection terminals must be reattached to each wire. The necessity of such tasks involves an extremely large amount of time and effort.
Given this, a configuration is known for such a shrinkable tube in which, by including a slit running the entire length direction of the shrinkable tube, an object to be covered can be accommodated within the shrinkable tube through the slit portion (see, for example, Patent Literature 1).